GM's OnStar team would really like us to stay on the electric side of the Chevy Volt's powertrain as much as possible. That's the selling point, after all. Rather than simply preach green driving and hope for the best, the division is testing a new EcoHub app that reminds Volt drivers just how miserly their plug-in hybrids can be. Qualifying owners who opt in or subscribe to OnStar have the Volt's energy usage costs compared to their home's total electricity bill, showing how much cheaper it can be to avoid the gas pump. There's more if money isn't enough of a motivator -- the app also builds in a counter that estimates how much gas Volt drivers are saving nationwide. The eco-friendly ego boost is currently limited to Android users participating in Pecan Street's smart grid project in Austin, but long-term plans have the app reaching iOS and all Volt fans eager to justify their ride.